In recent years, employed in a vehicle-mounted disk playback device for playing back an optical disk (hereinafter, referred to as a “disk”) such as a CD or a DVD is a slot-in system without a tray for loading and unloading a disk, such that the disk is directly inserted or loaded in a slit opening in order to be adapted to a narrow installation space. In the method, when a disk is inserted therein through a slit opening, the outer edge of the disk is detected at a previously determined position at which the disk is loaded to rotate a carrier roller, the disk is held between the carrier roller and a disk guide to be carried to a playback position where a turntable is located, the disk is then disengaged from the carrier roller and the disk guide, and is clamped against the turntable by a clamper descending from above.
Meantime, the disk playback device includes a variety of auxiliary mechanisms in addition to the mechanisms for performing the above-described main operations. Particularly, in the case of a vehicle-mounted disk playback device vulnerable to vibrations from the external, a vibration insulating mechanism is provided on a playback deck where a travel mechanism of an optical pickup is assembled. The vibration insulating mechanism has a structure for creating a floating state in which the playback deck is supported by a chassis base with a dumper or the like to insulate the vibrations. The playback deck is locked by a lock member during non-use and during disk carrying operation for loading and unloading the disk, while the playback deck is released from the lock by the lock member to be placed in a floating state during playback.
The outline of the operation of the disk playback device from the disk loading to the playback start including the lock operation and the unlock operation of the playback deck will be explained with the internal structure of the disk playback device shown in FIG. 9.
A disk (not shown) loaded in the disk playback device is gripped between a rotating carrier roller 1 and a disk guide (not shown) located above the carrier roller to be carried until the central hole of the disk is positioned above a turntable 7. At this moment, a lever member 2 abutting against the outer periphery of the disk is counterclockwise rotated by the conveyance force of the disk, and a tip portion of the lever member 2 moves a lock member 3 toward the front side of the device. By this movement, the lock member 3 is linearly displaced by a rack section engaging with a gear of a gear unit 8 rotated by a motor 10.
A clamp member 4, which is located above the turntable 7 and engaged with the lock member 3, begins to descend by the movement of the lock member 3 to cause a clamper 5 attached on the clamp member 4 to abut against the top face of the disk. Further, in order to carry the disk, the carrier roller 1, which is normally urged to the side of the disk guide located above the roller by a spring force, begins to descend to thus move away from the disk guide, when the inclined end of the lock member 3 abuts against the carrier roller by the movement of the lock member 3. At this time, the disk is held by an urging force of the descending clamper 5 from the top and an urging force of the carrier roller 1 from below, is lowered as the carrier roller 1 lowers, and is clamped against the turntable 7 on the playback deck 6.
The lock member 3 moves furthermore even after the disk clamps against the turntable 7; thus, another lock member 16 also begins to move, and the playback deck 6 is unlocked to go to a floating state. When the playback deck 6 is unlocked, a spindle motor is driven to rotate the disk clamped against the turntable 7, and an optical pickup 11 reads a record surface of the disk while moving radially of the disk.
The lock operation and the unlock operation of the playback deck carried out by the lock member are performed in synchronization with the disk carrying operation during loading or unloading of the disk, and thus the lock and the unlock operations thereof use the conveyance force of the disk. The lever member for transmitting the conveyance force of the disk to the lock member is rotated or translated by abutting against the outer periphery of the disk to be carried, and then is fixed at a position remote from the disk by a fixing member provided separately, while the disk is rotated and played back with being clamped against the turntable.
In this connection, Patent Document 1 discloses an example of a lever member for transmitting the conveyance force of a disk to a lock member in order to unlock a playback deck; however, the mechanism using a switching lever disclosed in Patent Document 1 is different from that of the present invention in the operating structure.    Patent Document 1: JP-A-2003-123362
In a lever member for transmitting the conveyance force of a disk to a lock member of a playback deck, as described above, in order to prevent the backlash of the lever member created by vibrations from the external, it is necessary to separately add thereto a means such as an urging member for normally urging the lever member. Therefore, the number of components increases, thus making it difficult to reduce the thickness of the product. Further, when the conveyance force of the disk to be carried is power-transmitted to the lock member, it is required to provide a mechanism such that the lever member can be operated by a small force without hindering the conveyance force of the disk.
In order to solve the above-mentioned problems, the present invention has been made, and an object of the present invention is to provide a disk playback device which makes it possible to reduce the thickness thereof by reducing the number of components of means for eliminating the backlash caused by external vibrations in a mechanism for transmitting the conveyance force of a disk and unlocking a playback deck.